36. OLIGOCENE TO EARLY MIOCENE SILICOFLAGELLATES FROM THE IVORIAN BASIN, EASTERN EQUATORIAL ATLANTIC, SITE 959¹

Maija E. Schellpeper² and David K. Watkins²

ABSTRACT

Silicoflagellate biostratigraphy and relative abundance were determined for Site 959 in the eastern equatorial Atlantic. Five silicoflagellate zones, Corbisema apiculata, Naviculopsis biapiculata, Naviculopsis lata, Naviculopsis ponticula, and Corbisema triacantha Zones, were used with the Distephanus speculum hemisphaericus Subzone occurring in the N. biapiculata Zone. The Naviculopsis quadrata Zone is missing between the N. ponticula and N. lata Zones, indicating a hiatus in the lower Miocene cores that corresponds to hiatus NH1. Silicoflagellate relative abundance was graphed as a measure of paleoproductivity for Hole 959A. One large pulse of productivity occurred in the latest early Miocene, right before silica deposition came to an abrupt halt in the earliest middle Miocene.

¹Mascle, J., Lohmann, G.P., and Moullade, M. (Eds.), 1998. Proc. ODP, Sci. Results, 159: College Station, TX (Ocean Drilling Program).
²Geology Department, University of Nebraska, 214 Bessey Hall, Lincoln, NE 68588-0340, U.S.A. 00091355@bigred.unl.edu